i now have a few of them with useless batteries as it is cheaper to buy new ones than replace a battery in them. i figured i could disable the charger and hook one up using the trailer battery for power. i would then have a clean source for 110v and an audible low voltage alarm.

I just replaced a Belkin "Bulldog" UPS after one of the switches went bad. A couple of years ago I replaced the batteries, but it required disassembling the chassis to get at them. The batteries were still good, so I use them in the AS with the Intellipower for a charger. I really liked the Bulldog Monitor software, it shows the incoming and outgoing voltage and frequency and can track the history for weeks or months. Requires a laptop though.

I just bought an APC unit. The batteries are much easier to replace, but the monitoring capability has fewer features.

As far as using an old one as a conditioner and warning device, I think your idea is great. I had planned to do that with the Belkin until the switch went bad. Let us know how it works out, and post a schematic.

Your idea will work..for limited periods of time, but most small (12 volt units) are built for short term, periodic use, and have very small heat sinks and usually no cooling fan. If you can keep your unit cool with the addition of a fan and a larger heat sink, they work great...The units larger than 500 watts are usually set up to run on 24 volt power, and use 2-12volt batteries in series.

Kevin

__________________If you don't know where you're going, any road will take you there

Your idea will work..for limited periods of time, but most small (12 volt units) are built for short term, periodic use, and have very small heat sinks and usually no cooling fan. If you can keep your unit cool with the addition of a fan and a larger heat sink, they work great...The units larger than 500 watts are usually set up to run on 24 volt power, and use 2-12volt batteries in series.

Kevin

good points! most UPS units i come across are home/small office type. the one at work for the phone system, had 3, 12v group 27ish sized batteries.

i'd use it for my laptop and i'm always connected via the shore line for power. maybe i'll put a 12v power supply fan in it. btw, the 600 watt APC uses a 2X6v pk.

ok, i emailed APC with a related question. i asked why, when i plug in a small desk type fan, the fan runs slow, this is the reply they sent:

Quote:

APC's Back-UPS line is designed for use with Computer-type loads only.
They are not designed to be used with motor loads or any other machinery.

One potential issue is the inrush current draw for a motor. It can easily
overload a Back-Ups UPS model. Secondly, these models of UPSs output a
Stepped-Approximated sine wave when on battery. This waveshape, while ideal for
computer-type equipment, is not particularly compatible with most motor loads.
The result may be that motors run very slowly, erratically, or not at all when
the UPS is on battery.

To protect this type of equipment, APC recommends first determining the
appropriate size UPS for the motor load in question. Ensure that the Volt Amp
rating of the UPS is sufficient to handle the start-up inrush current draw of
the motor. Secondly, select a UPS which outputs a Pure Sine Wave when on
battery, such as a Smart-UPS.

so, it might not be as useful as i had hoped, but still useful.

i have to relpy with model details and i'll find out if i can easily disconnect the charger portion of the unit.

i guess the information request landed in the legal department. this is the reply. i have to see if a friend can spare some time for me to resolve this.

Quote:

Unfortunately, our UPS units are not designed to be used with an independent
charger. We cannot recommend or support modifying our UPS units or using third
party batteries with the units for liability reasons. The BK300 carries a
lifetime equipment protection policy that would be voided if you were to modify
the unit or use it with a third party battery. The NETWORK POWERCELL BD only
carried a two year equipment protection policy, but for liability reasons we
still cannot support or recommend modifying these units or using them with third
party batteries.